Testers for shoes

ABSTRACT

A DYNAMIC TESTER FOR DETERMINING RESISTANCE TO CELLTEARING SEPARATION OF A RESILIENT CELLULAR ELASTOMER OUTSOLE AND A SHOE UPPER AT THE TOE PORTION OF A SHOE INCLUDING A SHOE HOLDING DEVICE AND A DEVICE FOR FLEXING EDGE EXTENSION PORTIONS OF THE OUTSOLE AT THE TOE PORTION REPEATEDLY IN A DIRECTION TO CREATE SEPARATIVE STRESS.

Sept. 278, '1971 E B HOVEY ETAL 3,608,372

TESTERS FOR SHOES Filed May 15, 1970 Eg?? i Wjw [zzz/m10 rs Eme/"sanElim/ey Deu/1&14 O. WET Bbl their/ Homey United States Patent Olce3,608,372 Patented Sept. 28, 1971 ABSTRACT OF THE DISCLOSURE A dynamictester for determining resistance to celltearing separation of aresilient cellular elastomer outsole and a shoe upper at the toe portionof a shoe including a shoe holding device and a device for diexing edgeextension portions of the outsole at the toe portion repeatedly in adirection to create separative stress.

FIELD OF THE INVENTION This invention relates to devices for testingstrength of attachment of outsoles to shoe uppers.

DESCRIPTION OF THE PRIOR ART At the present time the effectiveness ofbonding between llexible cellular elastomer outsoles particularlypolyurethane foam outsoles and shoe uppers is tested by applying forceto strip the outsole away from the shoe upper. In one such test, theforward end of a shoe, mounted on a last is disposed with the sole on afulcrum, the toe is pushed forward to bring the bond line between upperand sole into register with a wedge member and the heel end of the shoeis then pushed forward and downward to cause the wedge member toseparate the outsole from the upper. A gauge connected to the wedgemember measures the force necessary to separate the sole from the upper.Such tests provide important information on the performance to beexpected of a shoe in normal walking. However, exible cellular elastomersoles have shown a tendency to separate progressively from the shoeupper at the extreme forward portion of the shoe and this tendency isnot closely correlated with the bond strength test determined by presentdevices.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWING The inventionwill be described in connection with the attached drawing forming partof the disclosure of the present case in which:

FIG. l is a diagrammatic side elevational view of a tester according tothe present invention;

FIG. 2 is a fractional side elevational view on a larger scale withparts broken away showing at a stage in the movement of the stressapplying member of the tester where the member makes first Contact withthe forward portion of the outsole of a shoe;

FIG. 3 is a fractional side elevational view on the scale of FIG. 2 andwith parts broken away showing the distortion of the outsole of a shoeby the stress applying member of the tester at a further stage;

FIG. 4 is a fractional side elevational View on the scale of FIG. 2 andwith parts broken away showing the position of the stress applyingmember of the tester after passing and distorting the outsole and beforereturning to its initial position; and

FIG. 5 is a fractional side elevational view on the scale of FIG. 2 andwith parts broken away showing the stress applying member beingdisplaced around the outsole of a shoe in returning to its initialposition.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIG. l the tester ofthe present invention includes a support 10 for clamping a shoe 12 to betested in position for application of stresses against the outsole 14and a striker 16 including a stress applying member 18 having a soleedge engaging face 20 and a driving mechanism 22 to move the stressapplying member 18 repeatedly in a path in which the sole edge engagingface 20 will apply stress to the forward edge portions 24 of the outsole14.

Significant reproducible results from the tester require that the shoeupper 10 be supported in a manner which substantially prevents flexing.In general it is preferred to subject the shoe to testing while mountedon a rigid last or foot form 26 and the shoe support 10 of theembodiment shown in FIG. l is arranged for this factor. It will beunderstood that other devices for holding the shoe rigid may be used.The shoe support 10 includes a rigid base plate 28 on which is mounted aslidable plate member 30 which is adjustable toward and away from thestress applying member 18 by an adjusting screw 32 mounted in a bracket34 at the rear end of the base plate 28. A U-shaped member 36 isadjustably mounted on the slidable plate and dimensioned to allowinsertion of the heel end 38 of a lasted shoe 12 between the slidableplate 30 and the upper portion of the U-shaped member 36. A last clampplug 40 is mounted in the upper portion of the U-shaped member 36 inposition to be screwed down to force the heel end 38 of the lasted shoeupper 12 firmlyv tion of the clamp 42. Preferably the base plate 30 issupplied with a toe support Wedge 50 which is adjustable lengthwise ofthe slidable plate 30 for adjustment into contact with the upwardlycurved portion forward of the ball of the outsole 14 of a lasted shoeupper 12 mounted in the shoe support.

The stress applying member 18 presents a sole edge engaging face 20 withthe face transverse to the lengthwise axis of the shoe 12 and inclinedwith the upper portion nearer the shoe than the lower portion. Therelation of the shoe 12 and the sole edge engaging face 20i is adjustedsuch that the nearest edge, that is, the upper edge 52, of the face willjust graze the toe of the shoe upper 12 in movement of the stressapplying member 18 along its predetermined fixed path as shown in FIGS.2 and 3.v

Any suitable driving mechanism 22 adapted to move the stress applyingmember in a fixed path at controlled speed and frequency may be used.The driving mechanism shown in the drawing employs a cylinder I54constructed and arranged to reciprocate a piston and piston rod 56`using air pressure as the source of energy. Air for driving the pistonin the cylinder 54 is supplied from a pressure regulated air source 58through the connector hose 60' to the upper end of the cylinder. A shutolf valve 62 is provided between the hose and the top of the cylinder.The

stress applying member 18 is mounted on the end 63 of the piston rod 56.The cylinder 54 is rigidly supported by bracket members 64 secured toupright members 66 fixed to the base plate 28 and braced by the anglebars 68 which extend from a midportion of the upright members 66 to therear portion of the base plate 28. The length of stroke of the piston isdetermined by the member 70 fixed at one end to the piston rod 56 andwith its other end terminating in a ring 72 traveling on a valve controlrod 74. Adjustable stops 76 are provided on the valve control rod 74such that the ring moves the control rod 74 to reverse the direction ofair supply on contact with the stops.

In the construction shown in the drawing the stress applying member 18is shown as pivotally-mounted in a U-shaped piece 78 at the end of thepiston rod, the member 18 being constructed such that the weight of theportion -80 projecting on the opposite side of the pivot normallymaintains the sole edge engaging face 20 in position for engagement withthe forward edge portions 24 of an outsole 14 during the downward strokeas shown in FIGS. 3 and 4, but enables the member 18 to pivot downwardand away from the sole to pass around the sole edge during movement inthe opposite direction as shown in FIG. 5.

A stroke counter 82 is mounted on the upright member 66 with itsoperating arm 84 located to be moved by contact with the U-shaped member78 as the piston moves upward after completing each stroke.

As shown in FIGS. 2 and 3, downward movement of the stress applyingmember brings the sole edge engaging face 20 against the forward edgeportions 2-4 of the outsole 14, and distorts it inward and exes itdownward to exert a shearing stress due to the pressure and thecompression of the resilient outsole material while applying a downwardcomponent of force tending to separate the outsole 14 from the shoeupper 12. The stress applied to the joint 86 between the upper andoutsole is greater Where the outsole extends a greater distance beyondthe toe of the shoe upper; but this greater stress corresponds to thegreater stress to which such an outsole would be subjected when struckor kicked against an obstacle while being worn so that the greaterstress compensates and matches with the greater stresses encountered inactual use of a shoe having such greater sole edge extension.

Y. The angle of the outsole engaging face 20 to its direction ofmovement affects the character of stress applied to the outsole 14; andit appears that truest test results are secured where the outsoleengaging face 20 is at an angle of from about 15 to about 60 to thedirection of movement of the stress applying member 18. The thickness ofthe stress applying member 18 is designed to be suiticient that thelower edge 88 of the outsole engaging face is displaced away from theoutsole 14 by the angle to miss the forward edge 24 of the outsoleasshown in FIG. 2. A preferred stress applying member 1,8 has adimension of 11/2" in the direction of movement of the member 18 withthe upper edge 52 of the face 20 projecting 1/2 over the lower edge 88of the member and with a lateral width of the face of Zz. With thisarrangement, the rst contact between the outsole engaging face 20 andthe outsole 14 is between the angularly disposed face 20 and the upperedge of the outsole so that stress is applied progressively, rather thanas a hammer blow.

Also in order to insure results useful in predicting the resistance ofthe outsole to separation, it is important that the speed of the stressapplying member 18 not be excessive. Using the tester with a live inchstroke of the stress applying member 18, excellent results have beenobtained with the driving mechanism 22 set to provide a speed of theorder of 30 cycles per minute. Since the driving mechanism is controlledso that the piston travels at substantially constant speed except at thebeginning and end of its stroke, the linear speed of the stress applying4 member 18 as it engages the outsole 14 is of the order of tive feetper second.

Following the conditionss and arrangements above discussed it is foundthat the stress applied to the outsole 14 in any given stroke is notgreat enough to tear the outsole from the shoe. However, repeatedstrokes initiate lines of weakness which result in progressive tearingof cell walls and ultimate separation of the toe portion of the outsolefrom the shoe upper. Separation of the outsole from the shoe upper isconsidered to have occurred for purposes of testing when the ruptureextends back 1A" from the initial bond line between outsole and shoeupper.

Resistance to separation of cellular elastomer outsoles from shoeuppers, particularly of molded-on polyurethane outsoles from shoeuppers, under the action of the tester correlates well with resistanceto separation in actual wear. It has been found that shoes which willwithstand 250 strokes will provide acceptable performance in use andshoes which will withstand 375 or more strokes will provide superiorperformance.

'Having thus described our invention what we claim as new and desire tosecure by Letters Patent of the United States is:

1. Tester for determining resistance to separation of a resilientpolymeric outsole and a shoe upper at the toe portion of a shoe, saidtester comprising means for holding a shoe in a predetermined positionand means for dlexing edge extension portions of said outsole at the toeportion repeatedly in a direction to create separative stress betweensaid outsole and said shoe upper.

2. A tester for determining resistance to separation of a resilientpolymeric outsole and a shoe upper as defined in claim 1 in which saidflexing means includes a member having a sole edge extension-engagingface, said member being movable transversely to the lengthwise axis ofsaid shoe along a path in which said face engages said sole edgeextension and distorts it out of its path to liex the sole edgeextension away from said shoe upper.

3. A tester for determining resistance to separation of polymericoutsole and a shoe upper as defined in claim 2 in which said face isdisposed at an angle of from about 15 to about 60 to said path to createa component of force on said sole edge extension toward said shoe andsubstantially in the direction of the lengthwise axis of said shoe.

4. A tester forfdetermining resistance to separation of polymericoutsole and a shoe upper as defined in claim 3 in which said shoe isheld in a position relative to said path in which a forwardmost portionof the toe of said shoe upper is substantially in grazing relation to anedge of said sole edge extension-engaging face moving along said path.

5. A tester for determining resistance to separation of polymericoutsole and a shoe upper as defined in claim 4 in which said sole edgeextension-engaging face is mounted on a reciprocating member forengagement with said sole edge extension during movement in onedirection to apply separative stress and is displaceable around the soleedge extension during movement in the opposite direction along saidpath.

References Cited UNITED STATES PATENTS 1,487,561 3/ 1924 Hammes 73-72,106,171 1/19'38 Fogelson v 73-100 3,524,345 8/ 1970 Isaacson 73--150s. CLEMENT swIsHER, Primary Examiner U.S. Cl. X.R. 73-100

